This invention relates to a rotational machine having at least one free piston.
On consideration of the most general rotational machine (engine, or compressor or pump) it is fairly clear that a cylindrical piston in a round bore will provide the simplest compression seal, comparison may be made with the difficult linear seals of the Wankel engine. It is also apparent that, since for machining reasons toroidal or other curved cylinder shapes are impractical, the piston must run in a straight cylinder, with the consequence that there must be reciprocation motion for work to be done. In engines, if this work is extracted by any of the conventional reciprocating means (such as crank and con-rod, swash plate, roller and eccentric), these reciprocating means provide the ultimate engineering limitation, with conflicting demands for lightness in order to reduce the dynamic losses, and strength to transmit the power developed.
It is an object of the present invention to provide a rotational machine in which a linearly reciprocating, heavy piston, which is entirely free in a double ended cylinder, can be coupled to a rotating shaft.
It is a further object of the present invention to apply the mechanical development underlying the transmission of power between a free-piston and a rotating shaft in illustrative embodiments of such rotational machines in the form of an engine driven by an externally supplied motive pressure medium, a rotational machine for use in pumping fluid mediums, and a rotational combustion engine developing its own motive medium by internal combustion.
In the aforegoing and throughout the claims defining the invention the term "shaft" has been used merely to designate the structural aspect of the frame from which torque may be delivered. Examples are a spindle as in one preferred embodiment or an annular flange.